Two experiments will be conducted to examine sensory and sensory-motor fluctuations over the menstrual cycle and to determine the extent to which such fluctuations interact with diurnal variations in the same processes. In the first experiment, female subjects will be tested at four hour intervals on two days during the periovulatory and two days during the menstrual phase of their menstrual cycles of the following measures: tapping rate, grip strength, arm-hand steadiness, two-touch threshold, and critical fusion frequency. The visual threshold is measured with a signal detection paradigm. In the second experiment, adult women and men will be assessed on the same measures over an interval of 90 days. The results will be analyzed using time series techniques. In a third set of experiments, the nonverbal comunication of beliefs about the menstrual cycle will be explored, as well as the relationship of these beliefs to more general attitudes toward women.